The field of the invention is motors, and in particular examples described herein, motors of a type operated under PWM inverter motor control, including induction motors, brushless dc motors, and synchronous ac motors.
A motor can be excited in an ac induction mode, ac synchronous mode, or brushless dc (BLDC) mode using a dc link inverter to control three-phase switching of current in the windings of a 3-phase motor.
The increasingly sophisticated application of the contemporary technology often calls for several electromagnetic devices to be used simultaneously. For example, when an electric motor drive is used in a remote situation, various associated devices such as the auxiliary power systems, filters, transformers, and chokes may also be required. This creates an opportunity for cost reduction by forming multiple devices from individual components.
The present invention provides a method, an article of manufacture and an apparatus which utilizes corner scraps of stator lamination pieces of a motor to form magnetic cores for additional electromagnetic devices. Such devices can include, but are not limited to, DC-DC converters, transformers, filter chokes, AC output power supplies, and smoothing filters for the main stator windings in PWM applications. The corner cores are used for the magnetic cores of these associated devices.
The flux paths and the flux frequencies in the corner material of the present invention are different from those used in the conventional stators, such as the square stator lamination punching of a washing-machine motor. The stator portion of the punching of a washing-machine motor carries only the fundamental-frequency rotating flux. The corner cores of this invention share magnetic paths with the stator back iron.
In the present invention at least one auxiliary component can be added in each corner of the stator, and the auxiliary devices can be either single-phase or multiple phase components.
The invention maintains the original motor core length.
The invention may be applied to induction motors, brushless dc motors, wound-field synchronous motors and permanent-magnet (PM) motors.
The invention may be practiced with 2-phase modulation which lowers the switching losses of the main inverter.